Bashunosaurus

Not to be confused with Bashanosaurus.

Bashunosaurus is a genus of potentially macronarian sauropod dinosaur from the Middle Jurassic Shaximiao Formation of Kaijiang, China. The type and only species is Bashunosaurus kaijiangensis.

Bashunosaurus Temporal range: Middle Jurassic, 166–162 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Hypothetical illustration of Bashunosaurus as a macronarian
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	†Sauropodomorpha
Clade:	†Sauropoda
Clade:	†Macronaria (?)
Genus:	†Bashunosaurus Kuang, 2004
Species:	†B. kaijiangensis
Binomial name
†Bashunosaurus kaijiangensis Kuang, 2004[1]

Discovery

The holotype of Bashunosaurus, KM 20100, was discovered in sediments of the lower Shaximiao Formation in Maanping, Sichuan Province, China. It consists of six cervical vertebrae, eight dorsal vertebrae, a partial left scapula, and a right humerus, ulna, ilium, femur, tibia, and fibula. An additional right ilium, specimen KM 20103, was assigned as a paratype.^[2]

History

The name "Bashunosaurus kaijiangensis" first appeared in Ouyang's description of Abrosaurus in 1989,^[3] although without a description or diagnosis, making it a nomen nudum (i.e. a nickname that is unavailable for use as an actual scientific name). Li et al. (1999), however, attribute the naming to "Kuang, 1996", still considering it a nomen nudum.^[4] Although it was finally formally named by Kuang in 2004,^[2] George Olshevsky's influential online Dinosaur Genera List continued to list it as a nomen nudum and possible synonym of Datousaurus.^[5] It was largely ignored in modern literature until Dai et al.'s description of Yuzhoulong in 2022, where it is discussed.^[6]

Description

As a sauropod, Bashunosaurus would have been a large quadrupedal herbivore with a robust body. Kuang (2004) estimated its length as about 10–12 m (32.8–39.4 ft).^[2]

Classification

The precise classification of Bashunosaurus is unknown, with different authors proposing different ideas. Li et al. (1999) consider it a camarasaurid,^[4] while Kuang (2004) gives a more precise position in the Camarasaurinae, more derived than Abrosaurus but more basal than Camarasaurus.^[2] Molina-Perez and Larramendi (2020) list it as a primitive neosauropod similar to Bellusaurus, Daanosaurus, Dashanpusaurus and Klamelisaurus, although they comment that it is also "similar to Abrosaurus and Datousaurus".^[7] Dai et al. (2022) compare the taxon to Yuzhoulong, noting the fact it was described as a macronarian, although they caution that a reappraisal is needed to confirm this in a cladistic context.^[6][8]